package com.taylor.netty.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * @Desc : netty  实现websocket长连接服务端
 * @Author ： taylor
 * @Date ：2021/7/6 20:44
 */
public class NettyWebsocketServer {

    public static void main(String[] args) throws InterruptedException {

        //创建两个线程组
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        ServerBootstrap serverBootstrap = new ServerBootstrap();

        serverBootstrap.group(bossGroup, workerGroup);
        serverBootstrap.channel(NioServerSocketChannel.class);
        serverBootstrap.handler(new LoggingHandler(LogLevel.INFO));
        serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {

            @Override
            protected void initChannel(SocketChannel ch) throws Exception {

                ChannelPipeline pipeline = ch.pipeline();
                //因为基于http协议，使用http的编码和解码器
                pipeline.addLast(new HttpServerCodec());
                //是以块方式写，添加ChunkedWriteHandler处理器
                pipeline.addLast(new ChunkedWriteHandler());
               /*
                说明
                1. http数据在传输过程中是分段, HttpObjectAggregator ，就是可以将多个段聚合
                2. 这就就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                */
                pipeline.addLast(new HttpObjectAggregator(8192));
                /*
                说明
                1. 对应websocket ，它的数据是以 帧(frame) 形式传递
                2. 可以看到WebSocketFrame 下面有六个子类
                3. 浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议 , 保持长连接
                5. 是通过一个 状态码 101
                */
                pipeline.addLast(new WebSocketServerProtocolHandler("/netty"));
                //自定义的handler ，处理业务逻辑
                pipeline.addLast(new MyTextWebSocketFrameHandler());
            }
        });
        //启动服务器
        ChannelFuture channelFuture = serverBootstrap.bind(8888).sync();
        channelFuture.channel().closeFuture().sync();
    }
}
